Prime Lens worth it?

looking at picking up another lens and wondering if a prime lens is worth it for a 7D? ive never owned one before and i see some great pictures coming from full frame camera but i have yet to see any from crop sensors.

the two i am looking at are the 50mm 1.8 II and the 85mm 1.8.

Depends on what your goal is.

You should probably describe what you're trying to get from having a fixed focal length lens and faster focal-ratio and the things you can do with that, that you really want, compared to simply using what you have already. Really helps to know what you shoot. Walking around with a long fixed effective focal length will put a lot of limits on the content you can compose.

If your goal is shallow depth of field, then sure, get the fastest focal-ratio telephoto you can comfortably afford & use for your subject matter.

But if that's not your goal, then you really probably should consider why you're even looking at a prime, compared to a modern good quality zoom.

You also need to consider other things like how fast AF performs, etc, before comiting to something, just because its inexpensive. The 50 F1.8 family (II and STM both) are slow to focus for example. While the 85 F1.8 is blazing fast.

What subject matter are you thinking you need a prime for?

Very best,

MalVeauX wrote in post #18361462
Depends on what your goal is.

You should probably describe what you're trying to get from having a fixed focal length lens and faster focal-ratio and the things you can do with that, that you really want, compared to simply using what you have already. Really helps to know what you shoot. Walking around with a long fixed effective focal length will put a lot of limits on the content you can compose.

If your goal is shallow depth of field, then sure, get the fastest focal-ratio telephoto you can comfortably afford & use for your subject matter.

But if that's not your goal, then you really probably should consider why you're even looking at a prime, compared to a modern good quality zoom.

You also need to consider other things like how fast AF performs, etc, before comiting to something, just because its inexpensive. The 50 F1.8 family (II and STM both) are slow to focus for example. While the 85 F1.8 is blazing fast.

What subject matter are you thinking you need a prime for?

Very best,

Probably just portraits.

Just be aware that if you're planning to do portrait or event photography, where you're up close with people, on a crop body you'll need a correspondingly shorter focal length to get the same image framing relative to a full frame body. At the same f/ratio, a shorter focal length lens has a smaller diameter aperture and entrance pupil. This means that even at the same f/ratio, the shorter focal length lens will produce more depth of field. Aside from the image quality, from what I've seen here on POTN, portrait/event photographers like primes because they can get wider apertures (smaller f/ratios) and have more control over the depth of field. That will be more difficult to achieve with a crop body and a shorter focal length lens. That's just one of the reason why portrait/event photographers prefer full frame bodies.

Other than that, 50 and 85 are great focal lengths for portraits on a 7D.

Mike

gscrocker wrote in post #18361463
Probably just portraits.

For cheap, a 50mm STM would be the way to go. It's not fast to AF for action, but it's sharp wide open, accurate, well made, and really inexpensive for what it is. Would be more versatile for full body portrait, versus just busts, with a more intimate working distance instead of standing 20~30 feet away for a full body shot with a long lens.

There are many, many flavors of 50mm F1.4 as well out there, if you're not opposed to manual focus (live view makes it simple) you can experiment with cheap glass, or you could explore very good glass that is inexpensive because its manual.

Another good lens to consider is a Sigma 50 F1.4 or the Sigma 30 F1.4. The non-ARTs are cheap and still good. There's a 30 F1.4 for sale in the forum right now for $150 which is a great deal. Excellent little portrait lens for an APS-C.

Very best,

MalVeauX wrote in post #18361473
For cheap, a 50mm STM would be the way to go. It's not fast to AF for action, but it's sharp wide open, accurate, well made, and really inexpensive for what it is. Would be more versatile for full body portrait, versus just busts, with a more intimate working distance instead of standing 20~30 feet away for a full body shot with a long lens.

There are many, many flavors of 50mm F1.4 as well out there, if you're not opposed to manual focus (live view makes it simple) you can experiment with cheap glass, or you could explore very good glass that is inexpensive because its manual.

Another good lens to consider is a Sigma 50 F1.4 or the Sigma 30 F1.4. The non-ARTs are cheap and still good. There's a 30 F1.4 for sale in the forum right now for $150 which is a great deal. Excellent little portrait lens for an APS-C.

Very best,

Ill look into those sigma lenses.

The 50STM is cheap enough that it will be fun and interesting to try out, and you'll probably like it for portraits. I'd go that way.

I've never used the 50, but it must be fast enough AF for 'portraits'.

I've had 3 copies (2 used, 1 refurbished) of the 50mm II. None of them could focus in the light you want to use f/1.8 in. The 50mm STM is hugely better at AF. Optics are the same, but coatings are better on the STM.

I love my 85 1.8 on aps-c and full frame.

If you want a lens for indoor portraits in low light, the Canon 35F2IS is perfect. The 85F1.8 is a great lens on crop, but it is a bit on the long side for indoor portraits on crop. You will need a higher shutter speed for sharp photos, and much more working room. The view is narrow.
You should decide on your intended use before making a choice. Both of these lenses are very sharp, with fast and accurate AF. I would recommend the Canon 35.

artyH wrote in post #18361859
If you want a lens for indoor portraits in low light, the Canon 35F2IS is perfect. The 85F1.8 is a great lens on crop, but it is a bit on the long side for indoor portraits on crop. You will need a higher shutter speed for sharp photos, and much more working room. The view is narrow.
You should decide on your intended use before making a choice. Both of these lenses are very sharp, with fast and accurate AF. I would recommend the Canon 35.

Agreed. The 35IS is an extremely nice lens, on both aps-c and full frame.

Just to re-iterate, if you are looking at the "nifty fifty" get the 50 f/1.8 STM, not the "II" which has terrible, nearly unusable AF.

Take a look at the lens sample threads for the primes you are interested in,, in truth in most cases you will not be able to see which images are from FF sensors.

Yes there are people posting on this forum daily, including one I read today, that will claim HUGE differences in DOF when a fast lens is used on a crop body. I believe this is nonsense,. in practice I am seeing razor thin DOF on crop sensors as well as FF.


An example of the terrible deep depth of field that a crop sensor will ruin a fast lens with

IMAGE LINK: http://jakehegnauer.ze​nfolio.com/p62647257/e​554b8826

Would i get the same DOF from a variable zoom lens with the same size aperture and focal length? Im not sure what lens are out there but say a 35mm 1.8 vs a 17-35 1.8?

YES it would be the same ..


Sigmas 18-35 f1.8 is considered among the sharpest lens for apsc..

However , focus issues do exist .. so you may need to deel with that

The 35 f2 is , is the way id go in your spot , or a 50 , 85 is an awesome lens but can be difficult for indoor portraits unless you have the space

Reasonably priced remarkable glass......85 f/1.8. Buttery smooth bokeh. Purple fringing is commonly seen wideopen but so does many other longer prime lenses. The 85Lmk2 is just as guilty of making things purple

I highly recommend the Canon 35 f/2 IS prime. With a Canon crop factor of 1.6x you'll get get no distortion for closer portrait work. Very sharp lens that focuses very fast. The heavier vignette on a full frame isn't really seen on a crop sensor.